Regenerative heat exchangers



Jan. 2, 1968 A. KRITZLER REGENERATIVE HEAT EX CHANGERS 4 Sheets-Sheet 1Filed Oct. 12, 1965 lNvEn ToK ARTHMK KRITZLEE Jan. 2, 1968 A. KRITZLERREGENERATIVE HEAT EXGHANGERS 4 Sheets-Sheet 2 Filed Oct. 12, 1965INVENTOR ARTHMK KRITZLE Y LW Jan. 2, 1968 A. KRIT ZLER REGENERA'I'IVEHEAT EXCHANGERS 4 Sheets-Sheet 4 Filed Oct. 12. 1965 INVENTOE ARTWKKRITZLEQ my Wm United States Patent 3,361,193 REGENERATIVE HEATEXCHANGERS Arthur Kritzler, 25 Fliessenhardtstrasse, 5995 Freudenberg,Kreis Siegen, Westphalia, Germany Filed Oct. 12, 1965, Ser. No. 495,195Claims priority, application Germany, Oct. 16, 1964, Reg. No. (utilitymodel) A 22,583 6 Claims. (Cl. 165-10) ABSTRACT OF THE DISCLOSURE Thepack of plates which is disposed in the chamber of a regenerative heatexchanger and which comprises corrugated plates alternating with flat orundulated plates comprises at least one sub-pack which is substantiallyin parallelogram form together with at least one sub-pack which iswedged shaped but not a parallelogram which are assembled together toform a pack which is trapezoidal in cross section.

This invention relates to regenerative heat exchangers of the kind whichcomprises, inter alia, a substantially cylindrical regenerative heatexchange member, hereinafter referred to as a regenerator, which issubdivided by radial walls and partitions and by concentric andsubstantially cylindrical walls and partitions to form chambers whichare substantially of trapezoidal shape when viewed along or parallel tothe axis of the regenerator, and which extend substantially the whole ofthe axial length of the regenerator, which chambers are each adapted toreceive a pack of plates, the pack of plates in all of the chambersproviding the heat exchange mass of the regenerator.

A pack of plates, when disposed in its chamber, also is of trapezoidalshape in end elevation, by reason of its side nearer to the axis of theregenerator having to be shorter than the side remote from the saidaxis.

The pack of plates, in many cases, comprises corrugated platesalternating with flat or undulated plates, the latter plates providingabutments for the ridges of the corrugations of the former plateswhereby passages are provided along which gaseous fluids flow in order,in one event to give up heat to the plates, and in another and alternateevent, to take up heat from the plates. The corrugations in the formerplates extend substantially parallel to the axis of the regenerator, andfrom end to end thereof, so that the said gas flow passages also extendsubstantially parallel to the axis of the regenerator and from end toend thereof.

In the art of regenerative heat exchange regenerators, plates arereferred to as corrugated plates when they are provided with sharplyangular and deep corrugations to provide a transverse thickness, betweenthe planes of the ridges on opposite faces, of approximately mm. to 7mm., whereas plates are referred to as being undulated when they areprovided with sharply angular or sinuous corrugations which are shallowto provide a transverse thickness, between the planes of the ridges onopposite faces, of approximately 2.5 mm. Furthermore, when undulatedplates alternate with corrugated plates, while the corrugations of thecorrugated plates extend substantially parallel to the axis of theregenerator, the corrugations of undulated plates extend at an angle ofsubstantially 30 degrees to the said axis; thereby, the ridges of thecorrugated plates extend across the abutting ridges of the undulatedplates.

Consequently, in order that a pack of plates should adopt the requiredtrapezoidal shape when in position in the regenerator chamber, it can bemade substantially rectangular in end elevation and then compressed,taperwise, to provide a shape with one side shorter than the oppositeside and with the other two sides tapering towards each other.Alternatively, the corrugated plates are made, by a complicated rollingprocess, so that the height of the corrugations (that is, the distancebetween the planes of opposite faces of the plates) varies graduallyfrom one edge which is parallel to the corrugations to the oppositeedge, for example, from a corrugation height of approximately 7 mm. atone said edge to a corrugation height of approximately 5 mm. at theopposite edge; thereby, when a plurality of such corrugated plates,alternating with flat or undulated plates, are assembled together toform a pack, the pack has its required trapezoidal shape without havingto be compressed.

In either event, a pack of plates so made has the disadvantage of havingdifferential hydraulic radii, which may be excessive on the outer longerside, that is the side remote from the axis of the regenerator, thusproviding a poor heat exchange coefficient, or which may be too small atthe inner shorter side, nearer the axis of the regenerator, with theattendant risk of the flow passages being plugged with soot or dirtdeposited by the flowing gases. When the corrugated plates are rolled toprovide a differential in the height of the corrugations, the virginflat plates must be cut to a definite shape and size before the rollingis effected, and the resultant shape may be affected by tolerances inthe thickness of the plates causing the preshaped virgin plate toproduce a larger or smaller resultant shape. Furthermore, the cost ofsuch rolling, including the manufacture of the special rolls required,is very large.

The object of the present invention is to provide a pack of plates for aregenerator which is of the required trapezoidal shape and which can beproduced cheaply and easily from corrugated plates having a constantcorrugation height.

According to this invention, a pack of plates for disposing in atrapezoidal chamber of a substantially circumferential regenerator of aregenerative heat exchanger comprising corrugated plates alternatingwith undulating or plain plates is characterised in that each corrugatedplate has corrugations all of equal height, and that at least one firstsub-pack which is substantially a parallelogram in cross section isassembled together with at least one second sub-pack which isrectilineal but not a parallelogram in cross section to provide a packwhich is trapezoidal in cross section, all of the plates in a subpackbeing parallel to each other.

Referring to the accompanying drawings:

FIG. 1 is a perspective view of a pair of alternating corrugated andundulated plates in a regenerator pack of plates;

FIG. 2 is a diagrammatic end elevation of a pack of plates as hithertoconstructed;

FIGS. 3, 4 and 5 are diagrammatic end elevations of packs of platesaccording to three dilferent embodiments of the invention.

Referring to FIG. 2, the pack 11 of plates shown therein is trapezoidalin end elevation, that is when viewed along or parallel to the axis ofthe regenerator, so that it can be placed in a similarly shaped chamberof the re generator with the short side 12 near the axis of theregenerator, the opposite longer side 13 remote from the axis, and thetwo other sides 14, 14 extending along radii of the regenerator.Corrugated plates 15 alternate with undulated plates 16 to provide gasflow passages 17 which each extend parallel to the axis of theregenerator and between the axial ends of the regenerator.

The arrangement of a corrugated plate 15 and an adjacent undulated plate16 is shown in FIG. 1, which illustrates how the ridges of thecorrugated. plate abut and lie across the ridges of the undulated platethereby to provide the gas flow passages 17.

The corrugations in the corrugated plates 15 have a height 18 varyingfrom approximately 7 mm. at the edge of the plate disposed at the side13 of the pack to approximately mm. at the edge of the plate disposed atthe side 12 of the pack. The outline of a regenerator chamber into whichthe pack of plates is placed is shown at 19. The plates 15 and 16 areheld together, to form the pack 11, by binding wires 20.

In the embodiment of the invention shown in FIG. 3 a sub-pack 21 ofalternating corrugated plates 22 and undulating plates 16 is provided asa core for the complete pack 23, the corrugations of the plates 22having a height 24 which is constant throughout each plate. All of theplates 22 and 16 are of the same width 33, which is substantially equalto the mean radial length of the subchamber 19. Thereby, the sub-pack orcore 21 is rectangular in end elevation as seen in FIG. 3, having thesides 25 of the rectangle substantially equal in length to the shortside 12 of the pack. The plates 22 and 16 in the rectangular sub-pack 21are bound together by encircling binding wires 20. In each of theremaining two triangles 26 at the outer sides 14- of the pack there isdisposed an assembly 27 of alternating corrugated plates and undulatingplates which is substantially a right-angled triangle, the alternatingplates having varying widths 2.8, 29, 3d and 31. Each assembly 27 issecured to the rectangular sub-pack 21 by nails 32 or other suitablefastening devices so as to form an integral trapezoidal pack 23. Thecorrugations in any corrugated plate in the sub-pack 21 and in thetriangular assemblies 27 are all of the same height 24, and consequentlythe corrugated plates which are used are comparatively cheap becausethey do not require to be produced by complicated and expensive rollingmethods. All of the plates in the pack 23 are substantially parallel toeach other.

In the embodiment of the invention shown in FIG. 4, two sub-packs 34,34. are each formed of alternating corrugated plates 22 and undulatingplates 16, the corrugations of the plates 22 all being of the sameinvariable height 24, the plates 22 and 16 being so assembled to getherthat each sub-pack 34 is of rhomboid form in end elevation, as seen inFIG. 4, having their end sides 35 substantially equal to half thedimension of the short side 12 of the complete pack 36. The twosub-packs 34 are disposed with a short side 35 of each co-planar to formthe short end 12 of the pack 36, with the two sub-packs diverging fromeach other to leave a triangular space therebetween which issubstantially filled with a triangular assembly 37 of alternatingcorrugated and undulating plates. The plates in the triangular assembly37 have varying widths, 38, 39, 40 and 41, and they are secured togetherby nails 32 or other suitable fastening means. The whole pack 36,comprising the two rhombic sub-packs 34 and the triangular assembly 37is bound together by encircling binding wires 21 to provide an integralpack. The corrugations in the corrugated plates 22 of the two sub-packs34 and the assembly 37 are all of the same height 24, and therefore allof the plates in a sub-pack 34 or in the assembly 37 are substantiallyparallel to each other.

An advantage provided by the construction shown in FIG. 4 is that only atriangular portion of the pack need be nailed. The outer binding wires20 hold all the plates of the pack together, even though the nailconnections 32 4 of the triangular parts of the pack loosen a little,for instance, during transportation of the packs. 7

The embodiment of the invention shown in FIG. 5 is a modification ofthat shown in FIG. 3, in that the pack 23 comprises a rectangularsub-pack 21 providing the core of the pack and two outer irregularlyshaped assemblies composed of alternating corrugated and undulatingplates, the plates in the assemblies 43 having varying widths 33, 4-4,45, 46 and 47. The assemblies 43 in FIG. 5 dir ter from the assemblies27 in FIG. 3 in that the wider plates, having the width 33, are disposedat the outside of the pack 23 while the shorter width plates aredisposed inwardly of the pack. Consequently, while the plates in thesubpack 21 are not parallel to the plates in the assemblies 43, all ofthe plates in the sub-pack 21 or in each of the assemblies 43 aresubstantially parallel to each other.

Obviously, in all of the embodiments shown in FIGS. 3, 4 and 5, theundulated plates 16 can be substituted by llat or uncorrugated plates,that is plates which are known in the art of regenerative heatexchangers as plain plates.

The packs of plates according to the present invention are simpler andcheaper to manufacture than previously, more particularly because allthe corrugated plates are rolled straight from the strip or platematerial and can be cut to the correct dimensions after rolling. Anotheradvantage is that the trapezoidal cross-sections of the packs can have agreater conical taper than the prior art packs can provide.

What I claim and desire to secure by Letters Patent is:

1. In a regenerative heat exchanger having a regenerative portioncontaining a mass of plates which comprises corrugated platesalternating with undulating or plain plates, each corrugated platehaving corrugations all of equal height, the improvement wherein themass of plates comprises a plurality of sub-packs wherein at least onefirst sub-pack is substantially a parallelogram in cross-section and atleast one second sub-pack is wedge-shaped and said at least one firstand second sub-packs are assembled together to form a pack which istrapezoidal in cross-section and wherein all of the plates in a sub-packare parallel to each other.

2. The improvement according to claim 1 wherein one first sub-pack iscentrally disposed between two outer second sub-packs.

3. The improvement according to claim 2 wherein each second sub-packcomprises plates which vary in width.

4. The improvement according to claim 3 wherein the shorter width platesare disposed towards the outside of the pack.

5. The improvement according to claim 3 wherein the shorter width platesare disposed toward the centrally disposed first sub-pack.

6. The improvement according to claim 3 wherein one second sub-pack iscentrally disposed between two outer first sub-packs.

References Cited UNITED STATES PATENTS 12/ 1928 Great Britian. 6/1962Great Britain.

ROBERT A. OLEARY, Primary Examiner.

T. W. STREULE, Assistant Examiner,

